| 摘要 |
PURPOSE: To accurately estimate the place of a head for propulsion even when the status of the soil of a propulsive object ground changes. CONSTITUTION: The quantity of a head 4 for propulsion displaced is obtained by an attitude-angle measuring means freely measuring an attitude angle in the vertical direction of the axial center of the head 4 for propulsion at every propulsion at a fixed distance while the angle of rotation of a guide body 7 is acquired by a rotational-angle measuring means for measuring the angle of rotation of the guide body 7 in the periphery of the axial center. Steering capacity obtained by the formula of (the quantity of displacement/the fixed distance)×(the quantity of a reference vector/the quantity of a current vector) is computed on the basis of the quantity of displacement, the quantity of the reference vector EO in the direction that an inclined pressure-receiving surface 7a is directed in an axial-center view acquired from the angle of rotation, and the quantity of the current vector E1 as the quantity of the vertical component of the quantity of the reference vector E0, and the place of the head 4 for propulsion after propulsion at the fixed distance is estimated on the basis of steering capacity and the angle of rotation. |
